Anyway, since you are running a transient case and it diverged in 15 or so iterations, does that mean that it diverged on the very 1st iteration?

Most likely, you have incorrect initial conditions or your mesh is really bad. I would check those first. Make sure your initial conditions for all variables are consistent. For transient simulations you often need to generate the initial conditions from another simulation.

Also check your mesh quality. Run the mesh check and see if there are any glaring issues.